Sparking plug.



No. 792,695. PATBNTED JUNE 20, 1905. E. B. CLARK.

SPARKING PLUG.

APPLICATION FILED NOV. 10, 1902. RENEWED FEB. 21.1905.

IINTTED STATES Patented June 20, 1905.

PATENT Fries.

EDWIN E. CLARK, OF CANTON, OHIO, ASSIGNOR OF THREE-FOURTHS TO EDMUND A. BALM, OF CHICAGO, ILLINOIS.

SPARKING PLUG.

SPECIFICATION forming part of Letters Patent No.

792,695, dated June 20, 1905.

Application filed November 10, 1902. Renewed February 21, 1905. Serial No. 246,777-

To all whom, it may concern:

Be it known that I, EDWIN E. CLARK, a citizen of the United States, residing at Canton, in the county of Stark and State of Ohio, have invented certain new and useful Improvements in Sparking Plugs; and I do hereby declare that the following is a full, clear, and exact description of the same, reference being had to the annexed drawings, making a part of this specification, and to the figures of reference marked thereon, in which Figure 1 is a sectional view. Fig. 2 is a view of the sparking end. Figs. 8 are views showing the different parts disconnected.

The present invention has relation to sparking plugs for use in gasolene-engines or other engines where combustion is brought about by an electric spark.

Similar numerals of reference indicate corresponding parts in all the figures of the drawlugs.

In the accompanying drawings, 1 represents the shell, which is screw-threaded upon its outer periphery at its attaching end and screwthreaded upon its inner periphery at its outer end. To the outer end of the shell 1 is attached the insulating holding-nut 2.

The current-conducting bar 3 is located sub-- stantially as shown in the drawings, and, as shown, it is extended into the shell 1 through the insulating-thimble 4, its inner end being preferably provided with the head 5 and its outer end screw-threaded for the purpose of receiving and holding the wire-connecting thumb-nut 6. The inner periphery of the shell 1 is provided with the shoulder 7, which shoulder'is for the purpose of receiving the flange 8, formed upon the insulating-thimble 4. The insulating-thimble 4 is also provided with the flange 9, and upon which flange the inner end of the nut 2 rests.

It will be understood that by providing the flanges 7 and 9 the insulating-thimble will be held against end movement in either direction and that the current-conducting bar 3 will be held against end movement by means of the head 5 and the metal cap 10.

Between the metal cap 10 and the bindingnut 6 is located a conducting-wire 11, which is extended from a suitable battery, and the 5 return-wire (not shown) connected in the usual manner.

To the head 5 or its equivalent are attached the sparking points 12. In the drawings four of these sparking points are illustrated; but a greater number may be employed or a number more than one, if desired. For the purpose of providing a suitable chamber in which the sparking points 12 are located the shell 1 is tapered toward the annular flange 7 and the insulating-thimble 4 tapered from its lower flange toward the head 5.

The object and purpose in employing a plurality of sparking points is to provide against the non-production of sparks if in the event one of the points should become insulated from any cause, such as a coating of soot; but by providing a plurality of sparking points this ditficulty is overcome, owing to the fact that if any one of the points is in proper condition to produce the proper spark the desired result will be accomplished, and in use it may occur that some one of the points may be inoperative at certain times and become operative by reason of any accumulation forming upon a particular point becoming removed from time to time. By this arrangement and by providing a plurality of points I produce a positive sparking device at all times and under all circumstances.

In use I prefer to form the insulatingthimble 4 from mica, as I consider this the best material for the purpose designed, the reason being that it better resists the heat and the plug does not become short-circuited, owing to the fact that mica remains in its original position and condition, whereas by the use of material liable to become broken by heat or other causes the plug proper is short-circuited, and of course, owing to the 9 short-circuiting, sparks are not produced.

The material used for the sparking points is preferably platinum or other suitable lowconducting material.

It will be understood that so far as producing the sparks is concerned the head 5 may be dispensed with; but I prefer to form the head for the double purpose of providing better means for attaching the sparking a head, sparking points extended from the head and connected thereto, said points and head located in the tapered chamber of the shell and a binding-cap connected to the shell, and a binding-nut located upon the conducting-bar all arranged, substantially as and for the purpose specified.

In testimony that I claim the above I have hereunto subscribed my name in the presence of two Witnesses.

EDWIN E. CLARK. Witnesses:

J. A. JEFFERS, F. W. BOND. 

